refactor(cli): make notebook read routing explicit

packages/opencode/src/kilocode/tool/notebook.ts

@@ -25,9 +25,11 @@ const render = (kind: "markdown" | "code", text: string) => {
   return `<${kind}_cell>\n${body}</${kind}_cell>`
 }
 
-export async function open(filepath: string): Promise<Readable | undefined> {
-  if (path.extname(filepath).toLowerCase() !== ".ipynb") return undefined
+export function isFile(filepath: string) {
+  return path.extname(filepath).toLowerCase() === ".ipynb"
+}
 
+export async function open(filepath: string): Promise<Readable> {
   const raw = (await Encoding.read(filepath)).text
   const data = parse(raw)
   if (!object(data) || !Array.isArray(data.cells)) return Readable.from([raw])

packages/opencode/src/tool/read.ts

@@ -359,8 +359,7 @@ export const ReadTool = Tool.define(
 // routed through TextStream.withFallback so non-UTF-8 files are decoded via
 // iconv. The body otherwise matches upstream.
 export async function lines(filepath: string, opts: { limit: number; offset: number }) {
-  const extracted = await Notebook.open(filepath) // kilocode_change - extract readable notebook cells before paging
-  if (extracted) return readLines(extracted, opts) // kilocode_change
+  if (Notebook.isFile(filepath)) return readLines(await Notebook.open(filepath), opts) // kilocode_change - extract readable notebook cells before paging
   return TextStream.withFallback(filepath, (stream) => readLines(stream, opts))
 }